Protein localization and dynamics within a bacterial organelle

H. Velocity Hughes (Lead / Corresponding author), Edgar Huitema (Lead / Corresponding author), Sean Pritchard, Kenneth C. Keiler, Yves V. Brun, Patrick H. Viollier (Lead / Corresponding author)

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    24 Citations (Scopus)

    Abstract

    Protein localization mechanisms dictate the functional and structural specialization of cells. Of the four polar surface organelles featured by the dimorphic bacterium Caulobacter crescentus, the stalk, a cylindrical extension of all cell envelope layers, is the least well characterized at the molecular level. Here we apply a powerful experimental scheme that integrates genetics with high-throughput localization to discover StpX, an uncharacterized bitopic membrane protein that modulates stalk elongation and is sequestered to the stalk. In stalk-less mutants StpX is dispersed. Two populations of StpX were discernible within the stalk with different mobilities: an immobile one near the stalk base and a mobile one near the stalk tip. Molecular anatomy provides evidence that (i) the StpX transmembrane domain enables access to the stalk organelle, (ii) the N-terminal periplasmic domain mediates retention in the stalk, and (iii) the C-terminal cytoplasmic domain enhances diffusion within the stalk. Moreover, the accumulation of StpX and an N-terminally truncated isoform is differentially coordinated with the cell cycle. Thus, at the submicron scale the localization and the mobility of a protein are precisely regulated in space and time and are important for the correct organization of a subcellular compartment or organelle such as the stalk.

    Original languageEnglish
    Pages (from-to)5599-5604
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume107
    Issue number12
    DOIs
    Publication statusPublished - 23 Mar 2010

    Keywords

    • Caulobacter
    • fluorescence loss in photobleaching/fluorescence recovery after photobleaching
    • polar organelle
    • protein localization
    • protein mobility
    • CAULOBACTER-CRESCENTUS
    • CELL
    • CYCLE

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